POS0958 PREVALENCE AND RISK FACTORS OF OSTEONECROSIS OF THE FEMORAL HEAD IN PATIENTS WITH ADULT-ONSET STILL’S DISEASE
Authors: S. Kasai, Y. Kondo, Y. Sakai, S. Kojima, H. Tamai, J. Kikuchi, K. Matsumoto, Y. Kaneko
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Adult-onset Still's disease (AOSD) is a rare systemic autoinflammatory disease, characterized by symptoms such as spiking fever, arthralgia, sore throat, and skin rashes. The detailed pathogenesis of AOSD is not yet understood, hence the management often involves the use of corticosteroids. Among glucocorticoid-associated complications, osteonecrosis of the femoral head (ONFH) is rare and not immediately life threatening, however, delayed diagnosis can lead to a significant reduction in patients' quality of life and often requires surgical treatment. Although it is of great importance for rheumatologists to understand ONFH, little is known about ONFH in patients with AOSD because most studies on ONFH in adult have focused on systemic lupus erythematosus (SLE) despite AOSD being heavily glucocorticoid-exposable similar to SLE. <h3>Objectives</h3> To investigate the prevalence of ONFH complications among AOSD patients and explore its risk factors. <h3>Methods</h3> We reviewed all consecutive patients with AOSD who have visited the Keio University Hospital from 2012 to 2022 retrospectively. We investigated the development of ONFH after treatment and assessed relevant clinical features and laboratory data. To compare the frequency of ONFH in patients with AOSD with that in those with other rheumatic diseases, we also investigated prevalence of OFNH in patients with other rheumatic musculoskeletal diseases including SLE, idiopathic inflammatory myopathy (IIM), and vasculitis who had a history of treatment with high-dose (0.8 – 1mg/kg) glucocorticoid. All statistical analyses were performed using JMP 15 (SAS Institute Inc., Cary, NC, USA). <h3>Results</h3> We included 108 AOSD patients in the analysis and collected information from their charts. The mean age of onset was 44 years old, and 77% of the patients were female. Out of 108 patients, 9 (8.3%) developed OFNH throughout the mean observation period of 12.8 years. All 9 patients with OFNH had a history of high-dose corticosteroid therapy, and 8 of 9 (88.9%) received glucocorticoid pulse therapy. Univariate analysis revealed that male and complication of serositis or remarkable leukocytosis (&gt;15000/µL) were associated with development of ONFH in AOSD patients, in addition to the history of treatment with high-dose glucocorticoid and pulse therapy (Table 1.) Next, we compared the frequency of ONFH development among 60 AOSD patients with high-dose corticosteroid treatment history with that of patients with other rheumatic diseases including SLE (n=312), IIM (n=84), small-vessel vasculitis (n=123), and large-vessel vasculitis (n=59). We identified that AOSD patients were second most likely to develop ONFH, following SLE; ONFH prevalence was 15.0% in AOSD, 20.5% in SLE 6.0% in idiopathic inflammatory myopathy, 1.6% in small-vessel vasculitis, and 1.6% in large-vessel vasculitis (Figure 1). <h3>Conclusion</h3> The complication of ONFH is frequent in patients with AOSD, the second highest after SLE in rheumatic musculoskeletal diseases. Glucocorticoid pulse therapy, high-dose glucocorticoid therapy, male sex, and remarkable leukocytosis and serositis are risk factors for developing ONFH. <h3>References</h3> [1]Choi HR, Steinberg ME, Y Cheng E. Osteonecrosis of the femoral head: diagnosis and classification systems. Curr Rev Musculoskelet Med. 2015;8(3):210-20. [2]Mzabi A, Fakhfakh R, Thabet M, Hassine IB, Anoun J, Karmani M, Ben Fredj F, Laouani C. Elderly-onset adult Still's disease. Reumatologia. 2021;59(3):188-196. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.